* {
    margin: 0;
    padding: 0;
}

body {
    width: 100%;
    color: #747474;
}

ul li {
    list-style: none;
}

#air {
    width: 100%;
    height: 130px;
}

// 导航模块
.nav {
    height: 650px;
    background: url('../img/join-bg.jpg') no-repeat;
    background-size: cover;
    display: flex;
    justify-content: center;
    align-items: center;

    .nav_text {
        color: #ffffff;
        text-align: center;
        letter-spacing: 2px;
        display: flex;
        flex-direction: column;

        :nth-child(1) {
            font-size: 80px;
            line-height: 96px;
            font-weight: 700;
        }

        :nth-child(2) {
            margin-top: 20px;
            font-size: 40px;
            line-height: 40px;
            font-weight: 400;
        }
    }
}

// 第一部分
.section-01 {

    .container {
        padding: 85px 228.359px;
    }

    .title {
        margin: auto;
        padding: 0px 30px 40px 30px;
        display: flex;
        flex-direction: column;
        justify-content: center;
        align-items: center;

        :nth-child(1) {
            margin-bottom: 16px;
            height: 41px;
            line-height: 41px;
            font-size: 32px;
            color: #333;
        }

        :nth-child(2) {
            margin-bottom: 20px;
            height: 34px;
            line-height: 34px;
            font-size: 15px;
        }

        :nth-child(3) {
            margin-bottom: 30px;
            width: 206px;
            border-bottom: 2px solid #ff6600;
        }
    }

    ul {
        margin-bottom: 25px;
        display: flex;
        flex-direction: row;
        justify-content: space-between;

        li {
            position: relative;
            margin: 0 15px;
            padding: 27px 20px;
            height: 319px;
            width: 33.33%;

            &:hover {

                .front,
                .back {
                    transform: rotateY(180deg);
                }
            }

            .front,
            .back {
                position: absolute;
                top: 0;
                left: 0;
                margin: 0 15px;
                padding: 27px 20px;
                width: 412.109px;
                height: 319px;
                border-radius: 7px;
                transition: all .5s;
                text-align: center;
                display: flex;
                flex-direction: column;
                justify-content: center;
                align-items: center;

            }

            .front {


                color: #FF9800;
                background: #F5F5F5;
                font-weight: 400;
                z-index: 1;
                backface-visibility: hidden;


                h2 {
                    width: 180px;
                    margin-bottom: 9px;
                    font-size: 32px;
                    font-weight: 400;
                }

                span {
                    margin-top: 15px 0;
                    width: 250px;
                    font-size: 15px;
                }
            }

            .back {

                background: #F5F5F5;
                font-weight: 400;

                .backinner {
                    transform: rotateY(-180deg);
                    display: flex;
                    flex-direction: column;
                    justify-content: center;
                    align-items: center;

                    :nth-child(1) {
                        margin-bottom: 9px;
                        font-size: 18px;
                        color: #000000;
                    }

                    :nth-child(2),
                    :nth-child(3),
                    :nth-child(4) {
                        margin-bottom: 20px;
                        font-size: 15px;
                        color: #333333;
                    }

                    :nth-child(5) {
                        padding: 13px 29px;
                        background: #FF8939;

                        a {
                            font-size: 14px;
                        }

                    }


                }
            }

        }
    }
}